<!DOCTYPE html>
<!--
Copyright 2016 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->
<script>
'use strict';

if (!window.CustomElements || window.CustomElements.hasNative) {
  if (!Polymer.Settings.useNativeShadow) {
    tr.showPanic(
        'Polymer error',
        'base should use native shadow when possible.');
  }
}
</script>
